/*
 *  ircd-ratbox: A slightly useful ircd.
 *  whowas.c: WHOWAS user cache.
 *
 *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
 *  Copyright (C) 1996-2002 Hybrid Development Team
 *  Copyright (C) 2002-2012 ircd-ratbox development team
 *  Copyright (C) 2016 William Pitcock <nenolod@dereferenced.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
 *  USA
 */

#include <ircd/stdinc.h>
#include <ircd/hash.h>
#include <ircd/whowas.h>
#include <ircd/match.h>
#include <ircd/ircd.h>
#include <ircd/numeric.h>
#include <ircd/s_assert.h>
#include <ircd/s_serv.h>
#include <ircd/s_user.h>
#include <ircd/send.h>
#include <ircd/s_conf.h>
#include <ircd/client.h>
#include <ircd/send.h>
#include <ircd/logger.h>
#include <ircd/scache.h>

struct whowas_top
{
	char *name;
	rb_dlink_list wwlist;
};

static rb_radixtree *whowas_tree = NULL;
static rb_dlink_list whowas_list = {NULL, NULL, 0};
static unsigned int whowas_list_length = NICKNAMEHISTORYLENGTH;
static void whowas_trim(void *unused);

static void
whowas_free_wtop(struct whowas_top *wtop)
{
	if(rb_dlink_list_length(&wtop->wwlist) == 0)
	{
		rb_radixtree_delete(whowas_tree, wtop->name);
		rb_free(wtop->name);
		rb_free(wtop);
	}
}

static struct whowas_top *
whowas_get_top(const char *name)
{
	struct whowas_top *wtop;

	wtop = rb_radixtree_retrieve(whowas_tree, name);
	if (wtop != NULL)
		return wtop;

	wtop = rb_malloc(sizeof(struct whowas_top));
	wtop->name = rb_strdup(name);
	rb_radixtree_add(whowas_tree, wtop->name, wtop);

	return wtop;
}

rb_dlink_list *
whowas_get_list(const char *name)
{
	struct whowas_top *wtop;
	wtop = rb_radixtree_retrieve(whowas_tree, name);
	if(wtop == NULL)
		return NULL;
	return &wtop->wwlist;
}

void
whowas_add_history(struct Client *client_p, int online)
{
	struct whowas_top *wtop;
	struct Whowas *who;
	s_assert(NULL != client_p);

	if(client_p == NULL)
		return;

	/* trim some of the entries if we're getting well over our history length */
	if(rb_dlink_list_length(&whowas_list) > whowas_list_length + 100)
		whowas_trim(NULL);

	wtop = whowas_get_top(client_p->name);
	who = rb_malloc(sizeof(struct Whowas));
	who->wtop = wtop;
	who->logoff = rb_current_time();

	rb_strlcpy(who->name, client_p->name, sizeof(who->name));
	rb_strlcpy(who->username, client_p->username, sizeof(who->username));
	rb_strlcpy(who->hostname, client_p->host, sizeof(who->hostname));
	rb_strlcpy(who->realname, client_p->info, sizeof(who->realname));
	rb_strlcpy(who->sockhost, client_p->sockhost, sizeof(who->sockhost));

	who->flags = (IsIPSpoof(client_p) ? WHOWAS_IP_SPOOFING : 0) |
		(IsDynSpoof(client_p) ? WHOWAS_DYNSPOOF : 0);

	/* this is safe do to with the servername cache */
	who->servername = scache_get_name(client_p->servptr->serv->nameinfo);

	if(online)
	{
		who->online = client_p;
		rb_dlinkAdd(who, &who->cnode, &client_p->whowas_clist);
	}
	else
		who->online = NULL;

	rb_dlinkAdd(who, &who->wnode, &wtop->wwlist);
	rb_dlinkAdd(who, &who->whowas_node, &whowas_list);
}


void
whowas_off_history(struct Client *client_p)
{
	rb_dlink_node *ptr, *next;

	RB_DLINK_FOREACH_SAFE(ptr, next, client_p->whowas_clist.head)
	{
		struct Whowas *who = ptr->data;
		who->online = NULL;
		rb_dlinkDelete(&who->cnode, &client_p->whowas_clist);
	}
}

struct Client *
whowas_get_history(const char *nick, time_t timelimit)
{
	struct whowas_top *wtop;
	rb_dlink_node *ptr;

	wtop = rb_radixtree_retrieve(whowas_tree, nick);
	if(wtop == NULL)
		return NULL;

	timelimit = rb_current_time() - timelimit;

	RB_DLINK_FOREACH_PREV(ptr, wtop->wwlist.tail)
	{
		struct Whowas *who = ptr->data;
		if(who->logoff >= timelimit)
		{
			return who->online;
		}
	}

	return NULL;
}

static void
whowas_trim(void *unused)
{
	long over;

	if(rb_dlink_list_length(&whowas_list) < whowas_list_length)
		return;
	over = rb_dlink_list_length(&whowas_list) - whowas_list_length;

	/* remove whowas entries over the configured length */
	for(long i = 0; i < over; i++)
	{
		if(whowas_list.tail != NULL && whowas_list.tail->data != NULL)
		{
			struct Whowas *twho = whowas_list.tail->data;
			if(twho->online != NULL)
				rb_dlinkDelete(&twho->cnode, &twho->online->whowas_clist);
			rb_dlinkDelete(&twho->wnode, &twho->wtop->wwlist);
			rb_dlinkDelete(&twho->whowas_node, &whowas_list);
			whowas_free_wtop(twho->wtop);
			rb_free(twho);
		}
	}
}

void
whowas_init(void)
{
	whowas_tree = rb_radixtree_create("whowas", irccasecanon);
	if(whowas_list_length == 0)
	{
		whowas_list_length = NICKNAMEHISTORYLENGTH;
	}
	rb_event_add("whowas_trim", whowas_trim, NULL, 10);
}

void
whowas_set_size(int len)
{
	whowas_list_length = len;
	whowas_trim(NULL);
}

void
whowas_memory_usage(size_t * count, size_t * memused)
{
	*count = rb_dlink_list_length(&whowas_list);
	*memused += *count * sizeof(struct Whowas);
	*memused += sizeof(struct whowas_top) * rb_radixtree_size(whowas_tree);
}